Dry cell



c. F. BURGESS DRY CELL Filed Sept. 11, 1923 I INVENTIOR C/mrles f'fiwgeq s BY v Patented Nov. 30, 1926.

UNITED STATES PATENT OFFICE.

CHARLES IF. BURGESS, F MADISON, WISCONSIN; ASSIGNOB T0 BURGESS BATTERYCOMPANY, OF MADISON. WISCONSIN, A CORPORATION OF W'ISCONSIN'.

DRY CELL.

Application filed September 11, 1923. Serial No. 662,064.

.The objects of the present invention will becomerlear from thefollowing description taken in conjunction with the accompanyingdrawings wherein Fig. 1 is a fragmentary section of a dry cellillustrating one embodiment of my invention, and v Fig. 2 is a similarsection of a modified form.

The dry, cells illustrated in the drawings are of the sizes commonlyused in flashlights and forwireless telegrapliy, but certain features ofmy invention may be used with advantage in dry cells of the larger sizesnow common- 1y used for telephone and ignition work.

In the embodiment illustrated in Fig. 1, the zinc cathode 1, which alsoserves 'as the container for other components of the cell, is ofseamless'sheetzinc shaped from a flat sheetby punching,jdrawing andupsetting operations, and consequently is without a longitudinal orcircumferential seam. Such seamless or drawn cups have a special advantage when used as an element of the invention herein claimed.Centrally positioned within cup 1 is a carbon rod 2 surmounted by abrass contact cap 3. The carbon rod is for the most part enveloped in acore 4 of depolarizing material, such as manganese dioxide, intimatelymixed with carbonaceous material, such as graphite, this core beingenveloped in a bibulous envelope of cheese cloth, or other suitablematerial, held in place by a wrapping of thread 5, or in other suitablemanner. Interposed between the wrapped core and the zinc cup is agelatinized electrolyte 6 compounded and used in accordance with knownpractice.

In accordance with the present invention a circumferential bead 7 isformed in the zinc cup near its top, or open end, as shown in thedrawing. ,.-Resting on the said bead is the means used for sealing thecup. In the embodiment shown in Fig. 1, the sealing means comprises awasher 8 of fibrous material, such as stiff paper suitably paraflined.

This washer rests directly on head 7 and forms a tight joint therewith,and also makes a snug fit with carbon rod 2.

terial 9, such as sealing wax, may be poured in above the insulatingwasher-8' while in a hot and fluid condition, and then me be allowed toharden and tightly seal olf the air space 10 which separates washer 8from the core 4 and paste 6.

. and stiff, and the upper edge of the core 4 of the cell may besomewhat can be maintained constant.

Sealing ma -In the embodiment illustrated in Fig. 2 where-in the partsare numbered similarly to Fig. 1, the fibrous washer 8 is relativelythick the zinc can is crimped inward and flattened against the outerface of this washer at 11 to hold the washer securely seated on bead 7.Such a closing of the cup is relatively air-tight, but I consider itbetter practice to pour oversaid washer a thin layer 9. of sealingmaterial,

suchas paralfin, allowing the paraflin to flow inward into contact withthe carbon rod 3, and thereby reenforcing the joint around the carbonrod where the washer may have been damaged or deformed through as-'embly manipulations, as by having been forced over the thin brass cup 3with which the carbon rod is surmounted.

\Viththe construction shown in Fig. 2,

higher while still maintaining an adequate air space 10 for thereception of gases given off by the cell in normal operation. In otherwords, the capacity of the cell can be increased through use of myinvention without increasing the overall dimensions of the cell, Thereare other practical advantages arising through the use of eitherembodiment of the present invention as herepointed out more at length.

The head 7 by forming a ridge of smaller diameter on the inside of thecan acts as a support or spacer for the washer, and makes possible theuse of smaller washers than usual, as it is not necessary to depend onthe frictional engagement of the washer with the inside of the can tohold the washer in place; The bead does not allow the washer to go belowa predetermined depth, and consequently, the air space between the topof the gelatinized electrolyte and the washer Even if the washer beconsiderably smaller in diameter than the can it will still make a closejoint v with the bead, and will prevent the hot fluid 109 sealingmaterial or wax from running down inside the air space above theelectrolyte. The bead also facilitates assembly by preventing the washerfrom twisting around at an angle as is sometimes the case when washers:are inserted in cups of usual construction not equipped with beads.

Another advantage-of the head is that it reenforces and strengthens thezinc can at its open end. A cell so reenforced is less 119 liable to bedeformed as the result of rough handling during storage and shipment.

When the zinc cups are of seamless construction, as illustrated in thedrawing, the bead 7 can .be readily rolled therein and is entirelysmooth and uniform through the Such is not the case and in addition tothe advantages of a longer core, and the reduction in cost of.

sealing material, it has the further advantagethat it is less affectedby heat after the cell is finished.

. The inside crimp at the top edge of the zinc cup materially stifi'ensthe top ofthe cup, and the thick, tight and immovable liber washer willstand much abuse, particularly against downward thrust which mightfracture a more brittle sealing means. \Vith dry cells, as ordinarilyconstructed, it often happens that when a cell is dropped, or when thecarbon rod is subjected to a sharp blow, the shock will crack thesealing wax, and the carbon rod may even be pushed down through thecracked seal with resultant cracking and virtual destruction of thefragile molded core with which it is encircled.

I claim:

1. The combination of a dry-cell electrode cup having a bead near itsopen end, a carbon rod within said qup, a core encircling said rod,.aflat washer resting on said bead and making a tight fit with said carbonrod said washer being spaced from the top 0 said core to form an airspace in uninter-' rupted communication with said core into which'gasesmay pass freely from said core, the upper edge of said cup being crimpedover the edge of said washer to make an air-tight closure for said cup.

2. The combination of a seamless dry-cell electrode cup having a beadnear its open end, an insulating washer resting on said head, a carbonrod fitting tightly in said washer, a core encircling said rod andspaced from said washer to form an air space in uninterruptedcommunication with said core into which gases may'pass freely from saidcore, and fusible sealing material above said washer and about said rodmaking an airtight closure for said cups In testimony whereof I aflix mysignature.

CHARLESE. BURGESS.

